UNIQUE FEATURES OF INTERNAL INITIATION OF HEPATITIS-C VIRUS-RNA TRANSLATION
UNIQUE FEATURES OF INTERNAL INITIATION OF HEPATITIS-C VIRUS-RNA TRANSLATION
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DOI：
10.1002/j.1460-2075.1995.tb00289.x
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发表时间：
1995-12-01
期刊：
影响因子：
11.4
通讯作者：
JACKSON, RJ
中科院分区：
文献类型：
--
作者：
REYNOLDS, JE;KAMINSKI, A;JACKSON, RJ
丙型肝炎病毒（HCV）RNA是否通过内部核糖体进入机制翻译的问题已经通过测试在双顺反子mRNA的两个顺反子之间插入HCV序列是否促进兔网织红细胞裂解物中下游顺反子的翻译来检验，缺失分析表明，有效的内部起始需要HCV基因组的一段从约40- 100个核苷酸延伸到约100个核苷酸。由于HCV多蛋白合成的真实起始密码子在核苷酸342处，这表明除了5 ′-UTR序列之外，内部起始需要短长度的HCV编码序列，这一发现在BT 7-H细胞的转染试验中得到证实，并显示与下游报道基因顺反子的性质无关，对编码序列的强烈需求与小核糖核酸病毒RNA翻译的内部起始形成鲜明对比，可能与此相关，还发现，当真正的起始密码子突变为非AUG密码子时，内部起始的效率仅略微受损，这再次与小核糖核酸病毒形成鲜明对比。编码序列是内部起始所必需的这一发现，对于设计实验来检测细胞mRNA翻译的内部起始具有重要意义。
The question of whether hepatitis C virus (HCV) RNA is translated by a mechanism of internal ribosome entry has been examined by testing whether insertion of HCV sequences between the two cistrons of a dicistronic mRNA promotes translation of the downstream cistron in rabbit reticulocyte lysates, Deletion analysis showed that efficient internal initiation required a segment of the HCV genome extending from about nucleotides 40-370 and that deletions from the 3'-end of this element were highly deleterious, As the authentic initiation codon for HCV polyprotein synthesis is at nucleotide 342, this demonstrates that, besides 5'-UTR sequences, a short length of HCV coding sequences is required for internal initiation, This finding was confirmed in transfection assays of BT7-H cells and was shown to be independent of the nature of the downstream reporter cistron, The strong requirement for coding sequences is in sharp contrast to internal initiation of picornavirus RNA translation, As a probable correlate with this, it was also found that the efficiency of internal initiation was only marginally compromised when the authentic initiation codon was mutated to a non-AUG codon, again in sharp contrast with the picornaviruses. The finding that coding sequences are required for internal initiation has important implications for the design of experiments to test for internal initiation of translation of cellular mRNAs.